This engraving refers to an important ceremony performed by the Rain Wizard when the wells run dry. 

The bottom of the image shows a huge mushroom cloud rising to the horizon (begai). We can also see the parliament building on the island of Badu (kwod), where the sorcerers and chiefs decide together when the rain should come. They decide to call the Rain Wizard, who performs the ritual at the top of the kwod. 

At the top of the image, the frogs represent the clouds. They sing along with the Wizard until the rain falls. The drops fall from the third frog to the largest at the base. This frog shows that the rain has finally arrived.